/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * libc/netdb/lib_dnsaddserver.c
 *
 *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <tinyara/net/ip.h>
#include <tinyara/net/dns.h>

#include "netdb/lib_dns.h"

#ifdef CONFIG_NETDB_DNSCLIENT

/****************************************************************************
 * Public Data
 ****************************************************************************/

#ifndef CONFIG_NETDB_RESOLVCONF
/* The DNS server address */

union dns_server_u g_dns_server;
bool g_dns_address;				/* true: We have the address of the DNS server */
#endif

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: dns_add_nameserver
 *
 * Description:
 *   Configure which DNS server to use for queries
 *
 ****************************************************************************/

#ifdef CONFIG_NETDB_RESOLVCONF
int dns_add_nameserver(FAR const struct sockaddr *addr, socklen_t addrlen)
{
	FAR FILE *stream;
	char addrstr[DNS_MAX_ADDRSTR];
#ifdef CONFIG_NETDB_RESOLVCONF_NONSTDPORT
	uint16_t port;
#endif
	int status;
	int ret;

	stream = fopen(CONFIG_NETDB_RESOLVCONF_PATH, "at");
	if (stream == NULL) {
		int errcode = errno;
		ndbg("ERROR: Failed to open %s: %d\n", CONFIG_NETDB_RESOLVCONF_PATH, errcode);
		DEBUGASSERT(errcode > 0);
		return -errcode;
	}
#ifdef CONFIG_NET_IPv4
	/* Check for an IPv4 address */

	if (addr->sa_family == AF_INET) {
		if (addrlen < sizeof(struct sockaddr_in)) {
			ret = -EINVAL;
			goto errout;
		} else {
			FAR struct sockaddr_in *in4 = (FAR struct sockaddr_in *)addr;

			if (inet_ntop(AF_INET, &in4->sin_addr, addrstr, DNS_MAX_ADDRSTR) == NULL) {
				ret = -errno;
				ndbg("ERROR: inet_ntop failed: %d\n", errcode);
				DEBUGASSERT(errcode < 0);
				goto errout;
			}
#ifdef CONFIG_NETDB_RESOLVCONF_NONSTDPORT
			/* Get the port number */

			port = ntohs(in4->sin_port);
#endif
		}
	} else
#endif

#ifdef CONFIG_NET_IPv6
		/* Check for an IPv6 address */

		if (addr->sa_family == AF_INET6) {
			if (addrlen < sizeof(struct sockaddr_in6)) {
				ret = -EINVAL;
				goto errout;
			} else {
				FAR struct sockaddr_in6 *in6 = (FAR struct sockaddr_in6 *)addr;

				if (inet_ntop(AF_INET6, &in6->sin6_addr, addrstr, DNS_MAX_ADDRSTR) == NULL) {
					ret = -errno;
					ndbg("ERROR: inet_ntop failed: %d\n", errcode);
					DEBUGASSERT(errcode < 0);
					goto errout;
				}
#ifdef CONFIG_NETDB_RESOLVCONF_NONSTDPORT
				/* Get the port number */

				port = ntohs(in6->sin6_port);
#endif
			}
		} else
#endif
		{
			nvdbg("ERROR: Unsupported family: %d\n", g_dns_server.addr.sa_family);
			ret = -ENOSYS;
			goto errout;
		}

	/* Write the new record to the end of the resolv.conf file. */

#ifdef CONFIG_NETDB_RESOLVCONF_NONSTDPORT
	/* The OpenBSD version supports a [host]:port syntax.  When a non-standard
	 * port is specified the host address must be enclosed in square brackets.
	 * For example:
	 *
	 *   nameserver [10.0.0.1]:5353
	 *   nameserver [::1]:5353
	 */

	if (port != 0 && port != DNS_DEFAULT_PORT) {
		status = fprintf(stream, "%s [%s]:%u\n", NETDB_DNS_KEYWORD, addrstr, port);
	} else
#endif
	{
		status = fprintf(stream, "%s %s\n", NETDB_DNS_KEYWORD, addrstr);
	}

	if (status < 0) {
		ret = -errno;
		ndbg("ERROR: fprintf failed: %d\n", errcode);
		DEBUGASSERT(errcode < 0);
		goto errout;
	}

	ret = OK;

errout:
	fclose(stream);
	return ret;
}

#else							/* CONFIG_NETDB_RESOLVCONF */

int dns_add_nameserver(FAR const struct sockaddr *addr, socklen_t addrlen)
{
	FAR uint16_t *pport;
	size_t copylen;

	DEBUGASSERT(addr != NULL);

	/* Copy the new server IP address into our private global data structure */

#ifdef CONFIG_NET_IPv4
	/* Check for an IPv4 address */

	if (addr->sa_family == AF_INET) {
		/* Set up for the IPv4 address copy */

		copylen = sizeof(struct sockaddr_in);
		pport = &g_dns_server.ipv4.sin_port;
	} else
#endif

#ifdef CONFIG_NET_IPv6
		/* Check for an IPv6 address */

		if (addr->sa_family == AF_INET6) {
			/* Set up for the IPv6 address copy */

			copylen = sizeof(struct sockaddr_in6);
			pport = &g_dns_server.ipv6.sin6_port;
		} else
#endif
		{
			nvdbg("ERROR: Unsupported family: %d\n", addr->sa_family);
			return -ENOSYS;
		}

	/* Copy the IP address */

	if (addrlen < copylen) {
		nvdbg("ERROR: Invalid addrlen %ld for family %d\n", (long)addrlen, addr->sa_family);
		return -EINVAL;
	}

	memcpy(&g_dns_server.addr, addr, copylen);

	/* A port number of zero means to use the default DNS server port number */

	if (*pport == 0) {
		*pport = HTONS(DNS_DEFAULT_PORT);
	}

	/* We now have a valid DNS address */

	g_dns_address = true;
	return OK;
}

#endif							/* CONFIG_NETDB_RESOLVCONF */
#endif							/* CONFIG_NETDB_DNSCLIENT */
